1. Preparation of four copoly-(L-glutamic acid, DL-serine), the molar ratios of the two amino acid residues were 4: 1, 3: 2, 2: 3 and 1: 4, by debenzylation of the corresponding four copoly-(γ-benzyl L-glutamate, O-benzyl DL-serine), was attempted. 2. The inter-and/or intra- molecular ester-linkages, formed during the debenzylation reaction between hydroxyl group of serine residue and carboxyl group of glutamic acid residue, was broken by treating with ...